The efficacy and safety of synchronous bilateral extracorporeal shock wavelithotripsy

Purpose: Bilateral renal calculi have traditionally been managed by staged extracorporeal shock wave lithotripsy (ESWL dagger) due to concern about bi lateral obstruction. We evaluated the safety and efficacy of synchronous bi lateral ESWL, in a large series of patients treated at our institution to d etermine the safety and efficacy of this controversial technique in what is to our knowledge the largest series to date. Materials and Methods: We retrospectively evaluated the records of 120 pati ents with a mean age of 48 years who underwent bilateral synchronous ESWL b etween 1987 and 1996. Of the patients 71 (59%) were male. Average followup was 21 months. ESWL was performed using a Dornier HM3 dagger lithotriptor i n all cases. Intraoperative technique and postoperative factors were analyz ed using the Pearson product moment correlation, the 2-tailed t test and mu ltiple regression analysis. Results: Mean stone size was 13 and 15 mm. on the left and right sides, res pectively. There was an average of 1.7 stones per renal unit. After 1 treat ment; 72 of the 120 patients (60%) were stone-free bilaterally, while 72% a nd 73% of left and right renal units, respectively, were also stone-free. M ean creatinine was similar preoperatively and postoperatively (1.46 and 1.4 1 mg./dl., respectively, p = 0.73). There was 1 or more complications in 18 cases. The majority of complications were minor with no long-term morbidit y or death and there was no case of bilateral obstruction or renal failure. Additional procedures were required in 19 patients (16%) due to significan t residual stone disease or obstruction during followup. Multiple regressio n analysis revealed that only patient age, a right ureteral stent and the n umber of shocks correlated with the complication rate. Stone size and numbe r independently increased the probability of treatment failure and a repeat procedure (p <0.05). Patients with stones 20 mm. or greater were at partic ularly high risk for treatment failure and additional procedures. A total o f 27 of the 35 patients (77%) with residual calculi and 13 of the 19 (68%) requiring additional procedures were in this high risk subgroup. Conclusions: Bilateral synchronous ESWL is safe and effective monotherapy f or bilateral urolithiasis. No patient had bilateral obstruction or renal fa ilure and no deterioration of renal function was detected at followup. I(Kn owing which patient populations are at higher risk for failure or complicat ions may guide decision making.